No one forecasts mountain weather, not even the locals. :-) Seriously
true year 'round, but especially 'tween seasons. Fall weather very unpredicatable.
Depends on the day (and it can change 2-3 times during the day.)

Just be aware that temperature declines with altitude at the rate of about
1 degree C for every 100 meters of altitude gain. Dampness or dryness
will moderate that some. Presence or absence of sun and wind will make
it _seem_ warmer or colder than the actual temperature. Mountaintops much
above 3,000 meters in the Swiss Alps are at or near freezing in July.